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Make trivial expansion detection more aggressive. Trivially expand macros

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like:  #define IS_BLAH() 1

llvm-svn: 38686
This commit is contained in:
Chris Lattner 2006-07-09 00:57:04 +00:00
parent 7818605f83
commit c239583433
1 changed files with 30 additions and 9 deletions
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39
clang/Lex/Preprocessor.cpp
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@ -478,6 +478,32 @@ void Preprocessor::RegisterBuiltinMacros() {
Ident__TIMESTAMP__ = RegisterBuiltinMacro("__TIMESTAMP__");
}
/// isTrivialSingleTokenExpansion - Return true if MI, which has a single token
/// in its expansion, currently expands to that token literally.
static bool isTrivialSingleTokenExpansion(const MacroInfo *MI) {
IdentifierInfo *II = MI->getReplacementToken(0).getIdentifierInfo();
// If the token isn't an identifier, it's always literally expanded.
if (II == 0) return true;
// If the identifier is a macro, and if that macro is enabled, it may be
// expanded so it's not a trivial expansion.
if (II->getMacroInfo() && II->getMacroInfo()->isEnabled())
return false;
// If this is an object-like macro invocation, it is safe to trivially expand
// it.
if (MI->isObjectLike()) return true;
// If this is a function-like macro invocation, it's safe to trivially expand
// as long as the identifier is not a macro argument.
for (MacroInfo::arg_iterator I = MI->arg_begin(), E = MI->arg_end();
I != E; ++I)
if (*I == II)
return false; // Identifier is a macro argument.
return true;
}
/// HandleMacroExpandedIdentifier - If an identifier token is read that is to be
/// expanded as a macro, handle it and return the next token as 'Identifier'.
@ -556,12 +582,7 @@ bool Preprocessor::HandleMacroExpandedIdentifier(LexerToken &Identifier,
++NumFastMacroExpanded;
return false;
} else if (MI->getNumTokens() == 1 &&
// FIXME: Fn-Like Macros: Fast if arg not used.
FormalArgs == 0 &&
// Don't handle identifiers if they need recursive expansion.
(MI->getReplacementToken(0).getIdentifierInfo() == 0 ||
!MI->getReplacementToken(0).getIdentifierInfo()->getMacroInfo())){
} else if (MI->getNumTokens() == 1 && isTrivialSingleTokenExpansion(MI)) {
// Otherwise, if this macro expands into a single trivially-expanded
// token: expand it now. This handles common cases like
@ -675,9 +696,9 @@ ReadFunctionLikeMacroFormalArgs(LexerToken &MacroName, MacroInfo *MI) {
unsigned MinArgsExpected = MI->getNumArgs();
// C99 expects us to pass at least one vararg arg (but as an extension, we
// don't require this).
if (MI->isC99Varargs())
++MinArgsExpected;
// don't require this). GNU-style varargs already include the 'rest' name in
// the count.
MinArgsExpected += MI->isC99Varargs();
if (NumFormals < MinArgsExpected) {
// There are several cases where too few arguments is ok, handle them now.